GM Service Manual Online
For 1990-2009 cars only

Setting The Radio With Theftlock

Theftlock™ is a security feature which may or may not be used. If Theftlock is not used, the radio will play normally. If Theftlock™ is used, the radio will be useless if stolen because it will be inactive.

If the battery power is lost for any reason, a secret code must be entered again before the radio will turn ON.

Complete the following steps in order to enter a security code into the system. Do not pause for more than 15 seconds between each step:

  1. Write down any number from 000 to 1999. Keep the number in a safe place.
  2. Turn the ignition switch to the ACCESSORY or RUN position.
  3. Turn the radio system OFF.
  4. Press and hold the buttons 1 and 4 together for approximately 6 seconds until a series of dashes show on the radio display.
  5. Press MIN.
  6. 000 will appear on the display.

  7. Press MIN again. Hold the MIN button until the last 2 digits of the code appear.
  8. Release the button.

  9. Press HR until the first 1 or 2 digits of the code appear.
  10. Press AM/FM. REP will appear on the radio display.
  11. Repeat Steps 5 through 7.
  12. Press AM/FM. SEC will appear on the display. SEC means that the audio system is secured.

The indicator light will also flash when the ignition is OFF. If the display shows a series of dashes, the verification steps were not successful. Repeat the procedure.

Unlocking The Secured Radio

If the radio system is secured, SEC shows on the display. Complete the following steps in order to disable Theftlock™. Do not pause for more than 15 seconds between the steps:

  1. Turn the ignition ON. Ensure that the radio system is OFF.
  2. The time will show on the display.

  3. Press the buttons 1 and 4 together until SEC shows on the display.
  4. Press MIN and 000 will appear on the display.
  5. Press MIN again and hold until the last two digits of the code appear. Release the button.
  6. Press HR until the first one or two digits appear.
  7. Press AM/FM radio. If a series of dashes display, you have disabled the theft deterrent feature.
  8. If SEC shows, the audio system is still secured.

Unlocking The Secured Radio After A Power Loss

The following actions occur when battery power is applied to a secured radio after a power loss:

    • The radio does not turn on.
    • LOC appears on the display when the ignition is ON.

Complete the following steps in order to unlock the unit:

  1. Turn the ignition to the ACCESSORY or ON position.
  2. Turn the radio to the OFF position.
  3. Press MIN.
  4. 000 will appear on the display.

  5. Press MIN again. Hold the MIN button until the last 2 digits of the code appear. Release the button.
  6. Press HR until the first one or two digits appear.
  7. Press AM/FM. SEC will appear and the unit will operate.
  8. If LOC shows, the numbers did not match. The unit is still locked.

Determining Factory Backup Code

If the security is activated and the radio is disconnected from the battery power, the radio will display LOC. The radio turns ON when the correct unlocking code is entered. If the customer's code is lost or unavailable, refer to the Dealer Communications System Bulletin or call Technical Assistance.